Bone cells, p9

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Osseous Tissue/Bone
  • Bone is a connective tissue
  • Relatively few, spread out through the bone
  • Abundant matrix ( water, collagen, mineral salts)

Calcification
  • Deposition of mineral salts in a framework of collagen fiber in which the tissue hardens

Bones Are Hard Yet Flexible
  • Hardness- provided by crystallized mineral salts
  • Flexibility- provided by collagen fibers (resistant to being stretched or torn)

Types Of Cells In Bone Tissue
1. Osteoblasts
  • Bone building cells
  • They create and secrete collagen and other materials needed to build the matrix
2. Osteocytes
  • Mature bone cells
  • Maintains metabolism of the bone
  • NO CELL DIVISION.
3. Osteoprogenitor
  • "Bone stem cell"
  • Found in the periosteum
  • Undergo cell division differentiate into osteoblasts
4. Osteoclasts
  • Large cell formed from the fusion of 10-20 monocytes
  • Concentrated in the endosteum


Compact Bone Tissue
  • Contains few spaces
  • Forms the exterior layer of all bones and the diaphysis of long bones
  • Provides protection and support
  • Resists stress produced bu weight and movement

Osteon
  • The basic unit of compact bone

Perforated Canals
  • Transverse canals that through compact bone
  • Carry blood vessels, lymphatic vessels, and nerves from the periosteum

Central (Haverian) Canal
  • Runs longitudinally through the bone
  • It is the center of the osteon
  • Contains blood vessels and nerves

Concentric Lamellae
  • Rings of hard calcified matrix surrounding the central canal

Lacunae
  • Means 'Little Lake'
  • Small spaces in between lamellae
  • contains osteons

Canaliculi
  • Minute canals that that radiate off the lacunae in all directions
  • Contains projections of the osteocytes
  • Connect lacunae creating a network throughout the compact bone to provide nutrients and oxygen to all the osteocytes and to get rid of waste

Spongy Bone
  • Does not contain osteons
  • Made of trabeculae
  • Trabeculae contain osteocytes within lacunae connected by canaliculi
  • Spongy tissue makes up most of flat, short and irregular bone
  • Forms most of the epiphyses of long bones
  • Spongy tissue is light, reducing the weight of the skeletal system
  • Red bone marrow is found in the spaces between trabeculae